Need power protection when starting

Howdy,

I have some sensitive ham radio gear in my vehicle which is often used when the car is turned off.  (All radios are wired directly to the battery.)  Last week when I started the car, I lost all of the memories programmed into one of the rigs.  What would be the best way to protect the my gear (besides turning it all off each time I need to start the car.)

I could see two possible approaches:

1.) put the radios behind a normally closed relay that opens when the starter wire goes hot;

2.) some type of capacitor in line with the radios.

Any ideas, guys? Thanks in advance.